As an alarm technician for 15 years I will say you need to go into programming with your keypad. Usually there is a default installer code such as 1234 or 4321. Some go into programming upon power up of the system after which you can enter the code. The code may be 6 digits to 4 digits long. It could be called a master code. All of the wireless installations I have done have been to go into programming, find the section to install devices, either pick the device type or "learn" in the transmitter.
First, write down your programming steps including the sensor ID's and codes. Some systems expect you to know what you are doing and time out on you without activity for a while.
You Learn the transmitter by either activating the sensor by installing the battery and either pressing a button on the sensor, activation of the reed switch by pulling away the magnet, or typing in the transmitter's ID code or serial number. Note, some systems have a house code and an individual ID code.
After learning the device it will either go to the next open slot for device programming or you have to tell the system the device type, such as entry door, perimeter door, interior follower, panic, etc. These are usually 1, 2 or 3 digit codes you enter. Some systems then have a response type which is in the reporting of the system to the central station and or sounding the siren. You now need to find out how to save and exit programming.
After programming, test your system to make sure it functions properly.